A dry etching apparatus using plasma is used as an etching apparatus in manufacture of a semiconductor integrated device such as an LSI. In this apparatus, while a wafer to be etched is disposed on a cathode of a planar electrode and etching gas is introduced into the apparatus, a high-frequency voltage is applied between a counter electrode (anode) and the cathode by a high-frequency oscillator, to thereby generate plasma of the etching gas between the electrodes. Positive ions serving as activated gas in the plasma enter a surface of the wafer, and etching is performed.
In the dry etching apparatus, metal contamination occurs when a metal component is used, and hence a silicon component is used. Representative examples of the silicon component are a focus ring that has a doughnut shape surrounding the wafer to be etched (Patent Literature 1), and a disc-like upper electrode (Patent Literature 2), for example. A focus ring for 300 mm wafer, which is mainly in current use, is expensive because the focus ring is fabricated from a silicon crystal ingot having a diameter of 320 mm or more.